esp: transition to message out phase after SATN and stop command

The SCSI bus should remain in the message out phase after the SATN and stop
command rather than transitioning to the command phase. A new ESPState variable
cmdbuf_cdb_offset is added which stores the offset of the CDB from the start
of cmdbuf when accumulating extended message out phase data.

Currently any extended message out data is discarded in do_cmd() before the CDB
is processed in do_busid_cmd().

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20210304221103.6369-38-mark.cave-ayland@ilande.co.uk>

1 files changed, 58 insertions, 14 deletions

diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 23fcaa9..0d5c07e 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -272,13 +272,15 @@ static void do_cmd(ESPState *s)
     uint8_t *buf = s->cmdbuf;
     uint8_t busid = buf[0];
 
-    do_busid_cmd(s, &buf[1], busid);
+    /* Ignore extended messages for now */
+    do_busid_cmd(s, &buf[s->cmdbuf_cdb_offset], busid);
 }
 
 static void satn_pdma_cb(ESPState *s)
 {
     s->do_cmd = 0;
     if (s->cmdlen) {
+        s->cmdbuf_cdb_offset = 1;
         do_cmd(s);
     }
 }
@@ -295,6 +297,7 @@ static void handle_satn(ESPState *s)
     cmdlen = get_cmd(s, ESP_CMDBUF_SZ);
     if (cmdlen > 0) {
         s->cmdlen = cmdlen;
+        s->cmdbuf_cdb_offset = 1;
         do_cmd(s);
     } else if (cmdlen == 0) {
         s->cmdlen = 0;
@@ -309,6 +312,7 @@ static void s_without_satn_pdma_cb(ESPState *s)
 {
     s->do_cmd = 0;
     if (s->cmdlen) {
+        s->cmdbuf_cdb_offset = 0;
         do_busid_cmd(s, s->cmdbuf, 0);
     }
 }
@@ -325,6 +329,7 @@ static void handle_s_without_atn(ESPState *s)
     cmdlen = get_cmd(s, ESP_CMDBUF_SZ);
     if (cmdlen > 0) {
         s->cmdlen = cmdlen;
+        s->cmdbuf_cdb_offset = 0;
         do_busid_cmd(s, s->cmdbuf, 0);
     } else if (cmdlen == 0) {
         s->cmdlen = 0;
@@ -341,6 +346,7 @@ static void satn_stop_pdma_cb(ESPState *s)
     if (s->cmdlen) {
         trace_esp_handle_satn_stop(s->cmdlen);
         s->do_cmd = 1;
+        s->cmdbuf_cdb_offset = 1;
         s->rregs[ESP_RSTAT] = STAT_TC | STAT_CD;
         s->rregs[ESP_RINTR] |= INTR_BS | INTR_FC;
         s->rregs[ESP_RSEQ] = SEQ_CD;
@@ -357,21 +363,22 @@ static void handle_satn_stop(ESPState *s)
         return;
     }
     s->pdma_cb = satn_stop_pdma_cb;
-    cmdlen = get_cmd(s, ESP_CMDBUF_SZ);
+    cmdlen = get_cmd(s, 1);
     if (cmdlen > 0) {
-        trace_esp_handle_satn_stop(s->cmdlen);
+        trace_esp_handle_satn_stop(cmdlen);
         s->cmdlen = cmdlen;
         s->do_cmd = 1;
-        s->rregs[ESP_RSTAT] = STAT_CD;
+        s->cmdbuf_cdb_offset = 1;
+        s->rregs[ESP_RSTAT] = STAT_MO;
         s->rregs[ESP_RINTR] |= INTR_BS | INTR_FC;
-        s->rregs[ESP_RSEQ] = SEQ_CD;
+        s->rregs[ESP_RSEQ] = SEQ_MO;
         esp_raise_irq(s);
     } else if (cmdlen == 0) {
         s->cmdlen = 0;
         s->do_cmd = 1;
-        /* Target present, but no cmd yet - switch to command phase */
-        s->rregs[ESP_RSEQ] = SEQ_CD;
-        s->rregs[ESP_RSTAT] = STAT_CD;
+        /* Target present, switch to message out phase */
+        s->rregs[ESP_RSEQ] = SEQ_MO;
+        s->rregs[ESP_RSTAT] = STAT_MO;
     }
 }
 
@@ -505,9 +512,27 @@ static void esp_do_dma(ESPState *s)
         }
         trace_esp_handle_ti_cmd(s->cmdlen);
         s->ti_size = 0;
-        s->cmdlen = 0;
-        s->do_cmd = 0;
-        do_cmd(s);
+        if ((s->rregs[ESP_RSTAT] & 7) == STAT_CD) {
+            /* No command received */
+            if (s->cmdbuf_cdb_offset == s->cmdlen) {
+                return;
+            }
+
+            /* Command has been received */
+            s->cmdlen = 0;
+            s->do_cmd = 0;
+            do_cmd(s);
+        } else {
+            /*
+             * Extra message out bytes received: update cmdbuf_cdb_offset
+             * and then switch to commmand phase
+             */
+            s->cmdbuf_cdb_offset = s->cmdlen;
+            s->rregs[ESP_RSTAT] = STAT_TC | STAT_CD;
+            s->rregs[ESP_RSEQ] = SEQ_CD;
+            s->rregs[ESP_RINTR] |= INTR_BS;
+            esp_raise_irq(s);
+        }
         return;
     }
     if (s->async_len == 0) {
@@ -655,9 +680,27 @@ static void handle_ti(ESPState *s)
     } else if (s->do_cmd) {
         trace_esp_handle_ti_cmd(s->cmdlen);
         s->ti_size = 0;
-        s->cmdlen = 0;
-        s->do_cmd = 0;
-        do_cmd(s);
+        if ((s->rregs[ESP_RSTAT] & 7) == STAT_CD) {
+            /* No command received */
+            if (s->cmdbuf_cdb_offset == s->cmdlen) {
+                return;
+            }
+
+            /* Command has been received */
+            s->cmdlen = 0;
+            s->do_cmd = 0;
+            do_cmd(s);
+        } else {
+            /*
+             * Extra message out bytes received: update cmdbuf_cdb_offset
+             * and then switch to commmand phase
+             */
+            s->cmdbuf_cdb_offset = s->cmdlen;
+            s->rregs[ESP_RSTAT] = STAT_TC | STAT_CD;
+            s->rregs[ESP_RSEQ] = SEQ_CD;
+            s->rregs[ESP_RINTR] |= INTR_BS;
+            esp_raise_irq(s);
+        }
     }
 }
 
@@ -944,6 +987,7 @@ const VMStateDescription vmstate_esp = {
         VMSTATE_UINT32(do_cmd, ESPState),
         VMSTATE_UINT32_TEST(mig_dma_left, ESPState, esp_is_before_version_5),
         VMSTATE_BOOL_TEST(data_in_ready, ESPState, esp_is_version_5),
+        VMSTATE_UINT8_TEST(cmdbuf_cdb_offset, ESPState, esp_is_version_5),
         VMSTATE_END_OF_LIST()
     },
 };